How will inflation rate be determined in ETH 2.0?

So i have a lack of understanding on this topic and a few questions: Who will decide on the future inflation rate of ETH2.0, how high will it be and can it be changed by the validators?

If the validators can change it, what would stop them from increasing it to maximize short term profits in case of having high time preferences? As not everbody is able to stake, by increasing the issuance rate, validators would increase their portion of ETHs total stake. So their would be an incentive to do so.

Would be glad to learn from you all 🙂